title: Control of the conformations of ion Coulomb crystals in a Penning trap.
abstract: Laser-cooled atomic ions form ordered structures in radiofrequency ion traps and in Penning traps. Here we demonstrate in a Penning trap the creation and manipulation of a wide variety of ion Coulomb crystals formed from small numbers of ions. The configuration can be changed from a linear string, through intermediate geometries, to a planar structure. The transition from a linear string to a zigzag geometry is observed for the first time in a Penning trap. The conformations of the crystals are set by the applied trap potential and the laser parameters, and agree with simulations. These simulations indicate that the rotation frequency of a small crystal is mainly determined by the laser parameters, independent of the number of ions and the axial confinement strength. This system has potential applications for quantum simulation, quantum information processing and tests of fundamental physics models from quantum field theory to cosmology.
authors.affiliation: QOLS Group, Department of Physics, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Mavadia
authors.forename: Joseph F
authors.initials: JF
authors.lastname: Goodwin
authors.forename: Graham
authors.initials: G
authors.lastname: Stutter
authors.forename: Shailen
authors.initials: S
authors.lastname: Bharadia
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Crick
authors.forename: Daniel M
authors.initials: DM
authors.lastname: Segal
authors.forename: Richard C
authors.initials: RC
authors.lastname: Thompson